/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * Copyright 2000-2002,2004 The Apache Software Foundation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.sun.org.apache.xerces.internal.util;

/**
 * A simple integer based stack.
 *
 * moved to com.sun.org.apache.xerces.internal.util by neilg to support the
 * XPathMatcher.
 *
 * @author Andy Clark, IBM
 */
public final class IntStack {

  //
  // Data
  //

  /**
   * Stack depth.
   */
  private int fDepth;

  /**
   * Stack data.
   */
  private int[] fData;

  //
  // Public methods
  //

  /**
   * Returns the size of the stack.
   */
  public int size() {
    return fDepth;
  }

  /**
   * Pushes a value onto the stack.
   */
  public void push(int value) {
    ensureCapacity(fDepth + 1);
    fData[fDepth++] = value;
  }

  /**
   * Peeks at the top of the stack.
   */
  public int peek() {
    return fData[fDepth - 1];
  }

  /**
   * Returns the element at the specified depth in the stack.
   */
  public int elementAt(int depth) {
    return fData[depth];
  }

  /**
   * Pops a value off of the stack.
   */
  public int pop() {
    return fData[--fDepth];
  }

  /**
   * Clears the stack.
   */
  public void clear() {
    fDepth = 0;
  }

  // debugging

  /**
   * Prints the stack.
   */
  public void print() {
    System.out.print('(');
    System.out.print(fDepth);
    System.out.print(") {");
    for (int i = 0; i < fDepth; i++) {
      if (i == 3) {
        System.out.print(" ...");
        break;
      }
      System.out.print(' ');
      System.out.print(fData[i]);
      if (i < fDepth - 1) {
        System.out.print(',');
      }
    }
    System.out.print(" }");
    System.out.println();
  }

  //
  // Private methods
  //

  /**
   * Ensures capacity.
   */
  private void ensureCapacity(int size) {
    if (fData == null) {
      fData = new int[32];
    } else if (fData.length <= size) {
      int[] newdata = new int[fData.length * 2];
      System.arraycopy(fData, 0, newdata, 0, fData.length);
      fData = newdata;
    }
  }

} // class IntStack
